Prediction of Germination in Aged Seeds and Identification of New Seed Viability Biomarkers Using NMR Metabolomics.

The fast evaluation of seed performance is crucial for the agricultural industry. In this work, we apply NMR to identify specific metabolites that are related to the germination capacity of seeds. As our results show, NMR is a fast method with great potential to discover new accumulated metabolites during seed ageing and to predict the germination of a seed batch.

Analysis of multiple-herbicide resistant Amaranthus palmeri populations from Spain points to an introduction of the eccDNA from America.

Background: The herbicide-resistant invasive weed species Amaranthus palmeri threatens agricultural production and native plant ecology in Spain, as well as in other European countries. Understanding whether herbicide resistance alleles evolve in situ or are introduced via gene flow remains unclear. To address this, we characterized multiple resistance to acetolactate synthase (ALS)-- and 5-enolpyruvylshikimate-3phosphate synthase (EPSPS)-inhibiting herbicides in two Spanish A.

A PIF-SAUR module safeguards hypocotyl elongation from ABA inhibition in the dark.

Driven by cell elongation, hypocotyl growth is tightly controlled by light and responds to the stress signaling hormone abscisic acid (ABA). However, the molecular connections between ABA and light to control cell elongation are poorly understood. Here, we show that, in Arabidopsis, ABA inhibits hypocotyl elongation in the light but not in the dark.

Several point mutations and metabolism confer cross-resistance to ALS-inhibiting herbicides in Tunisian wild mustard.

A growing number of weed biotypes showing resistance to acetolactate synthase (ALS)-inhibitors have been reported in several species, notably including Sinapis arvensis L. Two putative resistant (R) populations of S. arvensis from Tunisia were subjected to greenhouse and laboratory investigations to validate resistance to ALS-inhibitors and to determinate the mechanisms involved.

Abscisic acid receptors functionally converge across 500 million years of land plant evolution.

Abscisic acid (ABA) functions as a central regulator of dehydration responses in land plants. As such, ABA signaling was pivotal in facilitating the colonization of terrestrial habitats. The conserved ABA signal transduction module consists of 2C-type protein phosphatases (PP2Cs) and their ABA-triggered inhibitors, PYRABACTIN RESISTANCE 1-like proteins (PYLs).

Plant BCL-DOMAIN HOMOLOG proteins play a conserved role in SWI/SNF complex stability.

The SWItch/Sucrose Non-Fermenting (SWI/SNF) complexes are evolutionarily conserved, ATP-dependent chromatin remodelers crucial for multiple nuclear functions in eukaryotes. Recently, plant BCL-DOMAIN HOMOLOG (BDH) proteins were identified as shared subunits of all plant SWI/SNF complexes, significantly impacting chromatin accessibility and various developmental processes in Arabidopsis. In this study, we performed a comprehensive characterization of mutants, revealing the role of BDH in hypocotyl cell elongation.

Plant BCL-Domain Homologues play a conserved role in SWI/SNF complex stability.

The SWItch/Sucrose Non-Fermenting (SWI/SNF) complexes are evolutionarily conserved, ATP-dependent chromatin remodelers crucial for multiple nuclear functions in eukaryotes. Recently, plant BCL-Domain Homolog (BDH) proteins were identified as shared subunits of all plant SWI/SNF complexes, significantly impacting chromatin accessibility and various developmental processes in Arabidopsis. In this study, we performed a comprehensive characterization of mutants, revealing a previously overlooked impact on hypocotyl cell elongation.

Modulation of abscisic acid signaling via endosomal TOL proteins.

The phytohormone abscisic acid (ABA) functions in the control of plant stress responses, particularly in drought stress. A significant mechanism in attenuating and terminating ABA signals involves regulated protein turnover, with certain ABA receptors, despite their main presence in the cytosol and nucleus, subjected to vacuolar degradation via the Endosomal Sorting Complex Required for Transport (ESCRT) machinery. Collectively our findings show that discrete TOM1-LIKE (TOL) proteins, which are functional ESCRT-0 complex substitutes in plants, affect the trafficking for degradation of core components of the ABA signaling and transport machinery.

Pro197Ser and the new Trp574Leu mutations together with enhanced metabolism contribute to cross-resistance to ALS inhibiting herbicides in Sinapis alba.

White mustard, (Sinapis alba), a problematic broadleaf weed in many Mediterranean countries in arable fields has been detected as resistant to tribenuron-methyl in Tunisia. Greenhouse and laboratory studies were conducted to characterize Target-Site Resistance (TSR) and the Non-Target Site Resistance (NTSR) mechanisms in two suspected white mustard biotypes. Herbicide dose-response experiments confirmed that the two S.

Transcription factors HB21/40/53 trigger inflorescence arrest through abscisic acid accumulation at the end of flowering.

Flowers, and hence, fruits and seeds, are produced by the activity of the inflorescence meristem after the floral transition. In plants with indeterminate inflorescences, the final number of flowers produced by the inflorescence meristem is determined by the length of the flowering period, which ends with inflorescence arrest. Inflorescence arrest depends on many different factors, such as the presence of seeds, the influence of the environment, or endogenous factors such as phytohormone levels and age, which modulate inflorescence meristem activity.

Alternative splicing as a driver of natural variation in abscisic acid response.

Abscisic acid (ABA) is a crucial player in plant responses to the environment. It accumulates under stress, activating downstream signaling to implement molecular responses that restore homeostasis. Natural variance in ABA sensitivity remains barely understood, and the ABA pathway has been mainly studied at the transcriptional level, despite evidence that posttranscriptional regulation, namely, via alternative splicing, contributes to plant stress tolerance.

Engineering plants using diverse CRISPR-associated proteins and deregulation of genome-edited crops.

The CRISPR/Cas system comprises RNA-guided nucleases, the target specificity of which is directed by Watson-Crick base pairing of target loci with single guide (sg)RNA to induce the desired edits. CRISPR-associated proteins and other engineered nucleases are opening new avenues of research in crops to induce heritable mutations. Here, we review the diversity of CRISPR-associated proteins and strategies to deregulate genome-edited (GEd) crops by considering them to be close to natural processes.

Abscisic acid mimic-fluorine derivative 4 alleviates water deficit stress by regulating ABA-responsive genes, proline accumulation, CO2 assimilation, water use efficiency and better nutrient uptake in tomato plants.

Water deficit represents a serious limitation for agriculture and both genetic and chemical approaches are being used to cope with this stress and maintain plant yield. Next-generation agrochemicals that control stomatal aperture are promising for controlling water use efficiency. For example, chemical control of abscisic acid (ABA) signaling through ABA-receptor agonists is a powerful method to activate plant adaptation to water deficit.

Structure-guided engineering of a receptor-agonist pair for inducible activation of the ABA adaptive response to drought.

Strategies to activate abscisic acid (ABA) receptors and boost ABA signaling by small molecules that act as ABA receptor agonists are promising biotechnological tools to enhance plant drought tolerance. Protein structures of crop ABA receptors might require modifications to improve recognition of chemical ligands, which in turn can be optimized by structural information. Through structure-based targeted design, we have combined chemical and genetic approaches to generate an ABA receptor agonist molecule (iSB09) and engineer a CsPYL1 ABA receptor, named CsPYL1, which efficiently binds iSB09.

Tribenuron-methyl metabolism and the rare Pro197Phe double mutation together with 2,4-D metabolism and reduced absorption can evolve in Papaver rhoeas with multiple and cross herbicide resistance to ALS inhibitors and auxin mimics.

Multiple resistance mechanisms to ALS inhibitors and auxin mimics in two Papaver rhoeas populations were investigated in wheat fields from Portugal. Dose-response trials, also with malathion (a cytochrome P450 inhibitor), cross-resistance patterns for ALS inhibitors and auxin mimics, alternative herbicides tests, 2,4-D and tribenuron-methyl absorption, translocation and metabolism experiments, together with ALS activity, gene sequencing and enzyme modelling and ligand docking were carried out. Results revealed two different resistant profiles: one population (R1) multiple resistant to tribenuron-methyl and 2,4-D, the second (R2) only resistant to 2,4-D.

Structure-Based Modulation of the Ligand Sensitivity of a Tomato Dimeric Abscisic Acid Receptor Through a Glu to Asp Mutation in the Latch Loop.

The binding of the plant phytohormone Abscisic acid (ABA) to the family of ABA receptors (PYR/PYL/RCAR) triggers plant responses to abiotic stress. Thus, the implementation of genetic or chemical strategies to modulate PYR/PYL activity might be biotechnologically relevant. We have employed the available structural information on the PYR/PYL receptors to design SlPYL1, a tomato receptor, harboring a single point mutation that displays enhanced ABA dependent and independent activity.

Evaluation of the Anti-transpirant Activity of ABA Receptor Agonists in Monocot and Eudicot Plants.

ABA receptor agonists capable of improving plant performance under drought conditions have been described during the last years. However, monocot and eudicot plant species respond differently to various agonists. Here, we provide a detailed methodology to evaluate the anti-transpirant activity of ABA receptor agonists in both monocot and eudicot plant species using infrared imaging and image data analysis.

Hydrotropism: Analysis of the Root Response to a Moisture Gradient.

Plant adaptation to environmental stress generated by low water availability requires continuous search for moisture niches in the soil. Thus, roots have evolved a hydrotropic response to sense differences in water potential of the soil, and through asymmetric growth, roots can bend to avoid lower water potential sites. Different experimental systems have been devised for hydrotropism assays, which usually rely on air moisture or split agar assays.

An Update on Crop ABA Receptors.

The hormone abscisic acid (ABA) orchestrates the plant stress response and regulates sophisticated metabolic and physiological mechanisms essential for survival in a changing environment. Plant ABA receptors were described more than 10 years ago, and a considerable amount of information is available for the model plant . Unfortunately, this knowledge is still very limited in crops that hold the key to feeding a growing population.

PYL8 ABA receptors of Phoenix dactylifera play a crucial role in response to abiotic stress and are stabilized by ABA.

The identification of those prevalent abscisic acid (ABA) receptors and molecular mechanisms that trigger drought adaptation in crops well adapted to harsh conditions such as date palm (Phoenix dactylifera, Pd) sheds light on plant-environment interactions. We reveal that PdPYL8-like receptors are predominantly expressed under abiotic stress, with Pd27 being the most expressed receptor in date palm. Therefore, subfamily I PdPYL8-like receptors have been selected for ABA signaling during abiotic stress response in this crop.

A Luciferase Reporter Assay to Identify Chemical Activators of ABA Signaling.

Plant stress tolerance relies on intricate signaling networks that are not fully understood. Several plant hormones are involved in the adaptation to different environmental conditions. Abscisic acid (ABA) has an essential role in stress tolerance, especially in the adaptation to drought.

Identification of ABA Receptor Agonists Using a Multiplexed High-Throughput Chemical Screening.

Small molecules that can activate abscisic acid (ABA) receptors represent valuable probes to study ABA perception and signaling. Additionally, these compounds have the potential to be used in the field to counteract the negative effect of drought stress on plant productivity. The PYR/PYL ABA receptors, in their ligand-bound conformation, inactivate protein phosphatases 2C (PP2Cs), triggering physiological responses that are essential for plant adaptation to environmental stresses, including drought.

Plant Osmotic Stress Signaling: MAPKKKs Meet SnRK2s.

Osmotic stress signaling in higher plants is crucial to cope with abiotic stress. RAF-like MAPKKKs are activated by hyperosmotic stress and activate downstream ABA-unresponsive and ABA-activated SnRK2s, integrating early osmotic stress and ABA signaling cascades. The connection of B2/B3/B4 RAF-like MAPKKKs with SnRK2s is a new paradigm in signal transduction.